1. Field of the Invention
The present disclosure relates to a position detection apparatus, a droplet discharging apparatus, a method for detecting a position, and a medium.
2. Description of the Related Art
Printers that convey a sheet and discharge ink at times when the sheet reaches an image forming position to form an image, have been known. For printers, needs for smaller sizes and portability have been increasing as downsized notebook PCs and smart devices have become popular. As such, printers having a sheet conveyance system omitted to be downsized (referred to as “handy mobile printers (HMPs)”, below) are coming into practical use. An HMP does not have the sheet conveyance system installed; the HMP is moved by a person to scan the surface of a sheet, and to discharge ink.
The HMP detects its own position on the surface of the sheet, and discharges the ink to form an image depending on the position. As a mechanism for detecting the position, a conventional HMP has been known that has two navigation sensors mounted on the bottom face (see, for example, Patent document 1). The navigation sensor is a sensor that optically detects fine edges on the surface of a sheet, to detect the amount of movement every cycle time. Having the two navigation sensors mounted makes it possible for the HMP to detect the angle of rotation in the direction horizontal to the surface of the sheet.
However, such a conventional HMP has a problem; it is difficult to reduce the size of the bottom part. First, even if having only one navigation sensor mounted, the HMP can detect a position. Two sensors are required for calculating the angle of rotation of the HMP with respect to the surface of the sheet, and for calculating the position based on the angle of the rotation. Moreover, to improve the precision of the detected angle of rotation, it is preferable to have a certain interval between the two navigation sensors. For these reasons, it is difficult to reduce the size of the bottom part of a conventional HMP.